Stoker



N. OSTRIN .Jan. 17, 1 939.

STOKER 1934 4 Sheets-Sheet 1 Filed Jui 12 N. OSTRIN Jan; 17, 1939.

STOKER Filed June 12, 1934 4 Sheets-Sheet 2 N. OSTRIN Jam 17, 1939.

STOKER Filed June 12, 1934 4 Sheets-Sheet 3 4 4 m. sum Tm E\ INVENTOR. ?Zorman' Oszm BY ATTORNEY.

Jan. 17, 1939.

N. STRIN STOKER 4 Sheets-Sheet 4 Filed June 12, 1934 INVENTOR. %mn Osrn ATTORNEY.

Patented Jan. 17, 1939 UNITED STATES PATENT OFFICE 15 Claims.

This application is a continuation in part of my co-pending application Serial #277,239, filed May 12, .928.

This invention relates to underied stokers in general, and more particularly the domestic type of stoker.

In the, usual type of domestic stoker the coal is advanced in the retort and, as it advances, it piles up between the tuyre blocks, where combustion` takes place. Most of the combustion takes place at and adjacent to the top surface of the coal` bed. Some coals are fast burning; others slow burning. To maintain the same combustion rate with a slow burning coal as with a fast burning coal a larger area fuel bed is required. For that reason a stoker that is designed to burn one particular grade of coal cannot be, used to full capacity when a different grade of coal is supplied, since the area of the burning surface of the coal bed is substantially unalterable. stoker manufacturers have, therefore, provided difierently designed stokers ,for sale in different sections of the country, where different types of coal are prevalent. This has prevented,standardization of stoker design and, for that reason, precluded obtaining the economy resulting from standardization, or, where standardization was had, it resulted in loss of efficiency due to the burning of one kind of coal in a stoker` designed for a different kind. It is one of the objects of the present invention to provide a stoker which, by a minimum change, can be adapted to use fast burning or slow burning coal. I construct the coal burning part of the stoker in such a manner that the shape of the tuyre blocks determines the area of the exposed portion of the fuel bed, and I support the tuyre blccks in such a manner as to facilitate ready removal of the same, and replacement by others. By merely changing tuyre blocks, without any great amount of labor, the stoker can be adapted to burn the various kinds of coal.

It is a further object of the present invention to provide a simple and efiicient end block for preventing the formation of a body of coke at the front of the retort and for preventng the escape of hopper gas at the front of the furnace. The Construction is such that the end block constitutes a simple hollow casting which may be made without special cores orthe like. Also, this casting is efliciently air cooled, thereby pre- Venting accidental overheating and resulting in- It is a still further object of the present invention to provide a stoker that eliminates the usual tendency for formation of dead coal pockets in the retort, that is, pockets of coal which do not move, but over which slides the coal to be b'urned. The coal in such pockets cokes after a period of time, and the pile of coke tends to increase in size, to the detriment of proper combustion. I eliminate this by suitably correlating the shap e of the rear of the retort to the position of the rear end of the coal feeding worm.

It is a further object of this invention to construct and arrange the tuyre blocks and the side plates, where side plates are used, so that they are held in place only by their own weight, and any plate or tuyre block may be taken out for replacement or repair by merely lifting the same out of the furnace and without disturbing any of the other tuyre blocks or plates. The inner end of each dead plate rests upon the sill of the wind box and the outer end butts against the side wall of the boiler.` This arrangement dispenses with the necessity of a special supporting structure for supporting the end plates.

The attainment of the above and other objects of the present invention will be apparent from the following specification taken in conjuncton with the accompanying drawings forming a part thereof.

In the drawings:

Figure 1 is a diagrarnmatic plan View of my stoker the portions that are old and well known being omitted;

Figure 2 is an enlarged fragmentary section taken on the line 2-2 of Figure 1;

Figure 3 is a perspective showing one of my tuyre blocks;

Figura 4 is a perspective of a portion of one of the plates placed between certain of the tuyre blocks;

Figure 5 is a fragmentary View showing the manner in which the retort fits under the boiler wall;

Figure 6 is a section taken on the line 6-6 of Figure 1;

Figure 7 is a top View of a stoker embodying my invention;

Figure`8 is a longitudinal section thereof;

Figure 9 is a section taken along the line 9--9 of F'gure 8;

Figura 10 is a section taken along the line l0-iil of Figure 8;

Figure 11 is a section taken along the line H-ll of Figure 8;

Figure 12 is a View of an end tuyre block that extends across the retort;

lil

Figure 13 is a section taken along the line l3-I3 of Figure 12;

Figure 14 is a perspective View of a section for extending the length of the wind box; and

Figure 15 is a perspective View of a section for extending the length of the retort.

Reference may now be had more particularly to the furnace shown in Figures 1 through 6. The front wall of the furnace is shown at IO, the side walls at l I, IZ, and the rear wall at l3. The walls constitute a water jacket. The two walls !5 and !6, located at equal distances from the walls H and z and therefore an equal distance from the center of the furnace, provide an enclosed air chamber l'i, into which air is forced by a blower in the usual manner to support the combustion of the coal. The wind box l'l is built up of a number of sections. The retort l8, which is made up of a desired number of sections, rests upon a number of spaced rods !9, which are supported by the opposite walls !5 and !6. The tuyre block 25 is of the general shape shown in Figures 2 and 3, and consists of an outer portion 26, which fits against the side wall 15 or !6 of the air chamber, and rests at its bottom 21 upon a sill in the side wall. The inner portion of the tuyre block has a number of openings ai, 32, 33, and 34 therein on one side of the center, and similar openings 35, 36, 31, and 38 on the other side of the center. In the illustration shown, the openings 3l-34 admit air in parallel jets as do the openings 35 to 38, the last mentioned jets being at an angle to the first mentioned jets. While in the illustration shown the jets admitting air at an angle to one another are on opposite sides of the tuyre block, it is not essential to the' invention that those jets be on opposite sides of the center of the tuyre block, and if desired, the adjacent openings, such as 31-32; 32-33 and 33-34 may admit air in non-parallel jets, each of which jets may be parallel to or nonparallel to the corresponding jet on the other side of the center of the tuyre block.

The inner wall of the tuyre block has a guiding leg 4l integral therewith, which guiding leg bears against the outside wall of the retort IS, the tuyre block resting on the retort. A brace 42 extending between the inner and outer walls of the tuyre block reenforces the same at the bottom. Two slots 43-44 admit air to the top and outer end of the tuyre block to burn coal that may pile over the edge of the tuyre. In the illustration shown, the slot 43 is an angle of 45 degrees to the horizontal, and the slot 44 at an angle of 30 degrees to the horizontal. While other angles of air admission may be used, it is desirable that the slots 43 and 44 should be at an angle to one another.

The side plates48 rest at their inner ends upon the walls ili-!5 of the wind box, and at their outer ends bear against the end of the boiler. A number of plates 48 are provided on each side of the stoker rather than a single plate in order that they may be more easily installed or removed, as a single plate would be rather heavy to handle. To prevent the plates 48 from wedging inward against the tuyre blocks, a number of plates 50 of a shape the sam-e as the end of a tuyre block are provided. These plates 50 are supported in the same way that' the tuyre blocks 25 are supported, and each plate 50 has a projection 5I against which the ends of the dead plates 48 bear. For each plate 48 there is provided two plates 58, one at each end. Between the end of r the fire tubes of the boiler and the last plate 48 is an opening 53 which is provided to receive the ashes. The ashes that may have formed on the plates or on top of the tuyre blocks may be manually pushed back by means of a rod or the like until they fall through the openings 53 into the ash pit 56 (Fig. 2) from where they may later be drawn forward and out.

It may be seen from the above Construction that any one of the tuyre blocks or of the dead end plates may be removed or replaced without in any Way disturbing any of the other tuyre blocks or end plates.

A motor 60, through a gear transmission BI, drives a ram 52 at a low speed with a constant stroke. The coal falls from a hopper 53 through an opening 64 in a plate 65 into the retort, and is pushed forward by the ram, the fresh coal being pushed forward and under the coal already in the retort. To vary the rate at which the coal is fed, there is provided a movable plate 65 which may be moved to cover a greater or lesser amount of the opening 54, thereby admitting more or less coal with each stroke of the ram as desired. At the end of the retort a stop guide 68 limits the movement of the coal and acts as an upward guide for any coal that may reach it. Any coal or ash that may rise to the top of the guide is pushed on to the end plate 69.

It is well known that the sediment which is ordinarily present in the water used will settle at the bottom of the boiler, frequently to the injury of the boiler. The sediment is a rather good heat insulator, and if the bottom of the boiler is subjected to great heat, the boiler shell may be burned. To prevent this, a number of dead blocks 10 are provided. While three of those blocks have been shown, it is understood that more or less may be used if desired. Frequently one or two dead blocks are sufficient, and sometimes they may even be dispensed with. The dead blocks of the same shape as the tuyre blocks 25 differ therefrom in that there are no air holes therein. Between the plate 65 and the bottom of the boiler wall lo, there is packed some fire clay or other refractory or heat insulating material 12. If a lesser number of tuyre blocks is used the plate 65 is pushed further into the furnace and the space between the plate and the Wall ID is filled with more refractory material.

The blower '55, the gear case 5 l, and the motor 50 are arranged in line with one another and parallel to the length of the boiler. The line 18 in Figure 1 :indicates` the center line of the blower 15 and. of the motor Gi). The center line of the retort IS is of course also the center line of the ram 52. This arrangement is not only compact, but also it is not in the Way when it is desired. to insert a long Operating tool through the door of the furnace.

In Figures 7 and 8 I show my invention applied to another type of furnace. A wind box u is located within the furnace and has a retort !02 therein, the wind box and the retort both supporting tuyre blocks !03. Coal is` fed into the retort by a worm !04 that extends through a worm housing !05 connecting the retort with a coal hopper !66. The worm l l is driven by a motor m through suitable speed-reducing gearing [08, said. motor also driving a fan !69 that forces air through a duet Hil into the air or wind box lili.

The air box lfii comprises a rear portion having a bottom 5, side walls HE, and a rear wall HT. At the front portion. of the` air box the side walls 6 are provided With flanges 8 for securing the air box in the furnace or for securing an extension to the air box. In this instancean extension is provided, of a shape such as is shown more particularly in Figure 14. The extension` is: merely a channel-shaped trough having a bottom !Za and side walls l-Z! that are adapted to form extensions of the bottom !5, and the side walls 6, respective-ly, to increase the length of the air box. Flanges &22422 and !Za-423 are provided for' securing the extension to the flanges !is-!IS of the front side of the rear section of the air box and to a front cover plate !25, respectiyely.

The retort !82 likewise comprises a rear section, the front face of which is provided with a flange, indicated at !27, to which is secured an extension !28 at its flange !29. A front fiange !30 on the extension !28` is provided for securing the retort to the front cover plate !25.

On smaller installations, burning less fuel, the extensions and !28 are omitted, the cover plate being Secured to the flanges !lB and !21. The front portion of the retort is supported by the cover plate !25. Where the length of the retort is short, no additional support is necessary. However, since it is desired to` adapt the same rear portions of the wind box and retort for long and for short installations, I provide the rear portion of the wind box with an upwardly-projecting support on which the rear portion of' the retort rests. Therefore cantilever stresses in the retort structure are avoided.

The tuyre blocks extend between the retort and the wind box, resting on both. Each tuyre block is removable independently of the others, being removable by merely lifting the same. No cement is used, and it is unnecessary to mfasten any bolts or the like. The assembly and disassembly of the tuyres is a simple operation, requiring no skill or knowledge of the structure of' the stoker. In a domestic installation the owner of the stoker may replace the tuyre blocks without diculty. The tuyre blocks along the two sides of the retort are of identical Construction, and all of the curved tuyre blocks along the back of the retort are of the same Construction, thereby facilitating standardization.

Each tuyre block comprisesan inner wall portion !48, an outer wall portion MI, and a top portion !42, defining a portion of an air passageway 33 through the respective tuyre blocks. The inner wall of each tuyre block has a number of openings !44 for admittng air into the coal bed. An. air opening !45 is provided at the junction of the outer and top Walls for admitting air to the rear of the tuyre blocks. One or more dead blocks !43 is provided at the front of each row of tuyre blocks on the two sides of the retort. These blocks are of the same general shape as the tuyre blocks, and difer therefrom only in that the dead blocks are not provided with air openings such as the openings At the front of the retort I provide a front tuyre !50, of a Construction such as is shown more particularly in Figures 12 and 13. This tuyre includes a plate portion I5! that extends across the retort and from which depends. an apron !52 that extends into the retort and terminates in a lower curved portion !53 that emb-races the worm !94. The plate has a top portion !54 and a bottom portion !55 from which extend side portions !Et-!55. This defnes air chambers !SL-!51 of the same general shape as the passageways !43 in the tuyre blocks, and communicating therewith as may be seen in Figure 10. A channel-shaped passageway !58 joins the air chambers !51 on thetwo sides of the retort. A cover plate !59 closes the front end of the chambers !51 and the passageway !58.

The downwardly-extending apron portion !52 is tapered toward the front of the furnace, forming a portion of a conical surface, as indicated at !62. The angle that this surface makes with the center line of the fuel feeding worm lll 't is approximately the same as the angle at which the coal would naturally rise as it leaves the worm housing !05. The purpose of this apron is to assure a forward movement of coal at the outer periphery of the worm at the point where the coal first leaves the worm housing. Without the conical portion !62 the coal at the forward end of the retort, adjacent the plate 25, is not advanced. After a period of time a body of coke is formed at that point, which soon becomes a clinker, that permits the escape of hopper gas. In my Construction the surface !62 bears against the coal, thus assuring a forward movement of the coal at that point. Thus no clinker is frmed, and the coal in engagement with the surface !62 prevents the escape of hopper gas through the front of the stoker by way of the worm housing !05.

The front tuyre slips into place, as does also the cover plate !59, in the same maner as do the tuyre blocks, and may lik-ewise be readily removed. This tuyre permits an air fiow across the front of the retort. Under some conditions this may be o-f importance. For instance, it may happen that coal piles up and burns in back of this tuyre, that is, along the wall !5 By reason of the ability of the air in the passageway !58 to circulat-e, this wall cannot become overheated to the extent of causing damage.

Around the wind box and lower section of the tuyre blocks there is a packing of refractory !65. As the coal is fed in the retort it rises over the tuyre blocks and, after combustion has taken place, the ash accumulates on this refractory, below the top of the tuyre blocks. All of the air passes through the wind box, around the retort, and through the tuyre blocks.

The worm housing !05 is provided with a removable cover ITE! which is bolted to the housing and to the hopper. The opening !11 through which the worm extends is enlarged above the worm, so that there is considerable spacing between the worm and the top of the opening, whereas there is no spacing at the bottom. Should some foreign article, such as a large bolt or the like. be contained in the coal and become wedged between the worm and the worm housing, it will be forced to the top: side of the worm, because of the space there available by reason of the enlargement of the opening !TL By removing the cover na it is possible to remove the obstruction easily, without the necessity of first removing all of the coal from the hopper It is to be noted that the height of the tuyre blocks is a considerable proportion of the total depth of the coal in the furnace. The greater the height of the tuyre blocks, and the greater the angle of inclination, the more coal can be burned in the furnace, it being merely necessary to change to rates of fuel and air supply. With a retort of a given size the area of the top surface of the burning coal bed is determined by a number of factors including the distance between the tops of the tuyre blocks on the two sides of the retort. The greater this distance the larger will be the area of the top surface of the fuel bed, other things being equal. It is to be noted that the front face of each tuyre block is at a considerable angle "a" to the vertical. Different standard tuyre blocks may be made, some wherein this angle is greater and 'some wherein this angle is smaller. The particular angle in any installation is determined by the type of coal that is burned. If a fast burning coal is to be used, I choose tuyre blocks wherein the angle "a" is small. If a slow burning coal is used, I choose tuyre blocks wherein the angle "a is large. Since the tuyre blocks extend upwardly from the retort by a considerable amount, a change in the angle "a" produces a considerable change in the distance between the top surface of the tuyre blocks and, correspondingly, a considerable change in the area of the top expos-ed surface of the fuel bed. Also, the same wind box, retort and fuel and air supply apparatus may be used on installations of difierent capacities. For instance, the stoker shown in Figure 8 may have a maximum coal burning Capacity of 40 pounds per hour. By using taller tuyre blocks the Capacity may be increased to '75 pounds per hour, by merely increasing the rates of fuel and air feed. This change is brought about only by changing the tuyre blocks, which are relatively inexpensive. With a comparatively small stock on hand a manufacturer can supply stokers for furnaces of difierent sizes and for coals of different types, by merely furnishing different tuyre blocks.

A stoker, once installed is expected to last a large number of years. During such time there may be changes in the relative costs of difierent kinds of coal. At the time of installation a fast burning coal may have been the most eeonomical in a given territory. Years later, due to price changes, a slow burning coal may be the most economical. If proper combustion efiiciency is to be maintained. it is necessary to change the stoker design when a change is made in the kind of fuel burned. In my stoker this is accomplish'ed by merely lifting out the old tuyre blocks and. setting down others. No bolting and Unbolting is necessary. No cementing of the new tuyre blocks is required.

It is to be noted that the rear of the worm extends substantially to the rear of the retort. The slope at the rear wall of the retort is such that, with the end of the worrn terminating in the position shown there is no tendency for a pocket of coal to form at the lower back portion of the retort and constitute a stationary base over which fresh coal is pushed. By making the lower rear surface of the retort as a smooth curve of a comparatively large radius of curvature, this source of trouble is eliminated.

In compliance with the requirements of the patent statutes I have here shown and described two preferred embodiments of my invention. It is, however, to be understood that the invention is not limited to these precise structures, the same being merely illustrative of the principles of the invention. What I consider new and desire to secure by Letters Patent is:

1. In a furnace, a wind box within the furnace, the inner side wall of said wind box having a longitudinally extending shoulder below the top thereof, a retort within the wind box and spaced from the side walls thereof, and tuyre blocks resting upon the retort and the shoulder and held against side movement by the portion of the wind box above the shoulder.

2. In a furnace, a wind box within the furnace, the inner side of said wind box having a longitudinally extending shoulder below the top thereof, a retort within the wind box and spaced from the side walls thereof, and tuyre blocks resting on the retort and on the shoulder of the Wind box and bridging the gap between the retort and the side walls of the wind box and vertically removable independently oi' one another.

3. In a furnace, a longitudinally extending wind box, a retort within the wind box and spaced from the side walls thereof, tuyre blocks resting within the wind box upon the retort and side walls of the wind box and bridging the spaces therebetween, side plates each supported at its inner edge upon one of said side walls and bearing at its outer edge against the furnace wall, and means supported on said side wall and retort and engaging the inner edge of the side plates to prevent movement thereof away from the furnace wall, said side plates being individually removable independently of one another.

4. In a furnace, a longitudinally extending wind box, a retort within the wind box, tuyre blocks resting within the wind box, side plates each supported at its inner edge upon one of said side walls and bearing at its outer edge against the furnace wall, and means supportel on said side wall and retort and engaging the inner edge of the side plate to prevent movement thereof away from the furnace wall, said side plates being individually removable independently of one another.

5. In a furnace, a longitudinally extending wind box, a retort within the wind box and spaced from the side walls thereof, tuyre blocks resting within the wind box upon the retort and side walls of the wind box and bridging the spaces therebetween, side plates each supported at its inner edge upon one of said side walls and at its outer edge including a portion bearing against the furnace wall.

6. In a furnace, a longitudinally extending wind box, a retort within the wind box and spaced from the side walls thereof, tuyre blocks resting within the wind box upon the retort and side walls of the wind box and bridging the spaces therebetween, 'side plates each supported at its inner edge upon one of said side walls and at its outer edge including a portion bearing against the furnace wall, and means supported on said side wall and retort and engaging the inner edge of the side plate to prevent movement thereof away from the furnace wall, said side plates and tuyre blocks being individually removable independently of one another.

7. A furnace including a wind box supplying all of the air of combustion, a retort within and spaced from the side walls of the wind box, tuyre blocks resting on the retort and on the wind box and bridging the spaces between the two, said tuyre blocks extending from the top of the retort upwardly and inclined at a substantial angle outwardly from the center of the retort and being of a height approximating the width of the retort, whereby a change in the angle of inclination produces an appreciable change in the area of the fuel bed at the top of the tuyre blocks, each of said tuyre blocks being held against upward removal solely by its own weight and being removable independently of the others by an upward lifting movement from its normal operative position, whereby a tuyre block may readily be replaced by another having a different angle of inclination to change the effective area of the fuel bed, said tuyre blocks being spaced from` the furnace walls by means having a top surface receiving the ash and incompletely burned fuel, said ash and fuel receiving surface being located appreciably above the top of the retort and below the top of the tuyre blocks, and said means closing oif the space between the wind box and the furnace wall and` being imperforate against the entrance of air into the combustion chamber through said top surface, said tuyre blocks having a plurality of vertically spaced air passageways directing air towards the center of the retort and also having air passageways directing an air supply to fuel particles that may reach said surface.

8. In a furnace, a longitudinally extending retort, means for advancing coal in the retort, a row of tuyre blocks on each longitudinally extending side of the retort, said tuyre blocks extending to a substantial height above the retort, the inner faces of the tuyre blocks being outwardly diverging so that the distance between the top inner edges of the two rows of tuyre blocks on opposite sides of the retort is substantially greater than the width across the top of the retort, means along the outer surfaces of the two rows of tuyre blocks for supporting the blocks against tilting in a direction away from the center of the retort, said means extending to a height substantially above the top of the retort and terminating in an imperforate ash and coal receiving surface below the top of the tuyre blocks, said tuyre blocks having a plurality of vertically spaced air outlets along their inner faces, and having, in addition, an air outlet in the region of the juncture of the outer and top surfaces of the tuyre blocks for supplying air of combustion to coal that reaches said ash and coal receiving surface, each of said tuyre blocks being held against vertical removal solely by its own weight, whereby the tuyre blocks are removable independently of one another.

9. In a furnace. a retort, means for advancing coal in the retort, tuyre blocks on the retort, the inner faces of the tuyre blocks being outwardly diverging so that the distance between the top inner edges of tuyre blocks on opposite sides of the retort is substantially greater than the width across the top of the retort, means along the outer surfaces of the tuyre blocks for supporting the blocks against tilting in a direction away from the center of the retort, said means extending to a height substantially above the top of the retort and terminating in an imperforate ash and coal receiving surface below the top of the tuyre blocks, said tuyre blocks having a plurality of vertically spaced air outlets along their inner faces, and having, in addition, an air outlet for supplying air of combustion to coal that reaches said ash and coal receiving surface, each of said tuyre blocks being held against vertical removal solely by its own weight, Whereby the tuyre blocks are removable independently of one another, said tuyre blocks being of a height, above the retort, approximating the width of the retort, whereby tuyre blocks of different angles of outward divergence Will produce substantial differences in the area of the fuel bed at the top of the tuyre blocks.

10. In combination with a retort and worm fuel feeding means in the retort, a hollow block having an imperforate plate portion that extends across the retort and which at its lower end merges into a projection that extends into the retort and terminates in a portion adapted to embrace the worm fuel feeding means in the retort, means constituting an integral part of the tuyre and, with the plate portion thereof, forming an air passageway through the block and across the retort, and a closure plate abutting against the block and forming an end closure for the air passageway, said last named means having' openings therein for permitting the circulation of cooling air through said passageway, and said projection being imperforate to prevent the' passage of gases through said projection into the retort.

11. Incombination with a retort and worm fuel feeding means in the retort, a hollow block having an imperforate plate portion that extends across the retort and which at its lower end merges into a projection that extends into the retort and terminates in a portion adapted to embrace the worm fuel feeding means in the retort, the portion of the projection in the retort that faces in the direction that fuel is fed in the retort being curved along substantially a conical surface, means constituting an integral part of the block and, with the plate portion thereof, forming an air passageway through the block and across the retort, and a closure plate abutting against the block and forming an end closure for the air passageway, said last named means having openings therein for permitting the circulation of cooling air through said passageway, and said projection being imperforate to prevent the passage of gases through said projection into the retort.

12. In a furnace, a wind box spaced from the furnace wall, a retort within the wind box and spaced at its upper edge from the wind box, tuyre blocks resting upon the retort and upon the wind box and bridging the space between the two, said tuyre blocks being removable independently of one another and each block being unrestrained against upward removal, and means for preventing side movement of the respective blocks while permitting freedom for upward movement of the same, said means comprising a packing of refractory material filling the space between the wind box and the furnace wall and terminating below the top of the tuyre blocks.

13. In a furnace, a wind box spaced from the furnace wall, a retort within the wind box and spaced at its upper edge from the wind box, tuyre blocks resting upon the retort and upon the wind box and bridging the space between the two, said tuyre blocks being removable independently of one another and each block being unrestrained against upward removal, and means for preventing side movement of the respective blocks while permitting freedom for upward movement of the same, said means comprising' a packing of refractory material filling the space between the wind box and the furnace wall and terminating below the top of the tuyre blocks, said tuyre blocks extending above the retort by an amount approximating the width of the retort with one face of the blocks constituting an upward continuation of the retort and inclined at an angle to the vertical, whereby the effective area of the fuel bed may be changed by using tuyre blocks of different angles of inclination.

14. In a furnace, a retort, means for advancing fuel thereinto, a row of tuyre blocks along one side of the retort, a row of tuyre blocks along the opposite side of the retort, means extending across the retort at the fuel supply end thereof and defining a chamber extending across the retort, said means abutting against the end tuyre blocks of the two rows and having openings establishing communication between the air passageways in the two rows of tuyre blocks and said chamber, said means including a portion extending into the retort and having an inclined lower surface limiting the angle of rise of the fuel in the retort at the point where the uel enters the retort which surface is imperforate to prevent the passage of gases therethrough into the retort.

15. In a furnace, a retort, a worm extending into the retort for advancng solid particles of fue] thereinto, and means for inhibiting turbulence of the fuel at the point of entrance of the worm into the retort, said means' including a member extending across the retort at the point of entrance of the worm, and to a depth at least slightly below the height to which the coal Would otherwise rise, whereby said member limits the rise of the fuel particles at the point where the worm enters the retort, said member being hollow and having openings therein for the passage of cooling air therethrough, and the portion of said membe'- that is within the retort being imperforate to prevent passage of gases therethrough into the retort and being upwardly tapered to control the movement of the coal under the action of the Worm at the point where the worm enters the retort.

NORMAN OSTRIN. 

